4100es - Amplifier Missing

Hi All

Looking for some adivce on the below issue, any direction would be appreciated.

I have a 4100es solution with 5 amplfiers spread across 3 boxes. (Pic Below). My problem is that the once the program is downloaded, I get a message
“Card 21 - 100W, Card Missing Failed”
“Card 22 - 100W, Card Missing Failed”
“Card 23 - 100W, Card Missing Failed”
“Card 24 - 100W, Card Missing Failed”

Basically what is happening is that once the communication leaves the 3Bay of Box 1 and goes to Bay 1 of Box 2 I am not getting any communication goind to the downstrean amplfiers.

What I have tried so far

I have changed the 3rd PDI, thinking it may be bad
I have changed the harness linking the Box1Bay3 Amplfier to the Box2Bay1 Amplfier, think the cable was bad
I have recehecked the cables to ensure that they are in the proper orientation ( P3 on the PDI in bay 3 of cabinet 1, to P1 on the PDI in bay 1 of cabinet 2)
I have swapped out amplfiers (all amplfiers are functional when swapped into Bay3)
I have changed the addresses of the amplfier (it always the same, the no communication to the 2nd box)

Note all the boxes are located next to each other.

I have reach out to tech support and while they have attempted to asssit i.e the above steps. I have hit a wall as to what else I can try. To me it seems as tho I may be missing some fundamental setting as all the hardware and cables and termination checks outs